The Breeding Bird Survey provides the most reliable data for monitoring the population of Townsend’s Warbler in Canada, despite poor coverage at high elevations and in wet forest habitat. The results suggest an estimated 41% decrease in the national population since the early 1970s. Results at the regional level vary, suggesting little overall change in the Northern Pacific Rainforest Bird Conservation Region (BCR) population, while the Great Basin, Northern Rockies and Northern Interior Forest BCRs show moderate to large decreases. All BCRs with reasonably reliable results are displayed below. The Townsend's Warbler is below the lowest acceptable level relative to its national population goal (see Canada graph below).
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
